EMPLOYEE BENEFIT PLANS - Changes in Plan Assets, Benefit Obligations, and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Change in plan assets:
Other adjustments	$ (14,476)	$ (9,903)	$ 4,988
Pension Benefits
Change in projected benefit obligation:
Beginning of year	887,477	833,939
Service cost	34,847	35,055	36,002
Interest cost	25,596	21,667	25,741
Actuarial (gain) loss	(243,769)	13,520
Plan amendment	0	0
Benefits paid, net of retiree premiums	(18,897)	(16,704)
End of year	685,254	887,477	833,939
Change in plan assets:
Fair value of plan assets at beginning of year	810,469	716,794
Actual return on plan assets	(171,517)	84,488
Employer contributions	17,275	25,891
Retiree contributions and Medicare part D subsidies	0	0
Benefits paid	(18,897)	(16,704)
Other adjustments	0	0
Fair value of plan assets at end of year	637,330	810,469	716,794
Reconciliation of funded status
Funded status	(47,924)	(77,008)
Unrecognized actuarial loss (gain)	(19,512)	12,323
Unrecognized prior service cost	3,205	4,174
Net amount recognized	(64,231)	(60,511)
Short-term portion of the pension benefits	2,600	2,100
Other Benefits
Change in projected benefit obligation:
Beginning of year	142,470	130,658
Service cost	6,830	6,072	7,945
Interest cost	4,009	3,217	4,305
Actuarial (gain) loss	(49,462)	5,276
Plan amendment	0	0
Benefits paid, net of retiree premiums	(2,095)	(2,753)
End of year	101,752	142,470	130,658
Change in plan assets:
Fair value of plan assets at beginning of year	169,436	147,057
Actual return on plan assets	(23,326)	23,160
Employer contributions	671	1,972
Retiree contributions and Medicare part D subsidies	2,176	2,199
Benefits paid	(4,421)	(5,057)
Other adjustments	150	105
Fair value of plan assets at end of year	144,686	169,436	$ 147,057
Reconciliation of funded status
Funded status	42,934	26,966
Unrecognized actuarial loss (gain)	(44,555)	(29,327)
Unrecognized prior service cost	1,583	1,738
Net amount recognized	$ (38)	$ (623)